Apparatus and method for displaying three-dimensional image

ABSTRACT

Disclosed is an apparatus and method for displaying a three-dimensional (3D) image. A 3D display apparatus includes an optical layer including a plurality of optical elements, a projector configured to scan a light onto the optical layer, and a processor configured to control a timing at which the projector scans the light onto the optical layer and generate a 3D image in a viewing space based on the timing at which the light is scanned onto the optical layer.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority from Korean PatentApplication No. 10-2018-0159967, filed on Dec. 12, 2018 in the KoreanIntellectual Property Office, the disclosure of which is incorporatedherein by reference in its entirety.

BACKGROUND 1. Field

Methods and apparatuses consistent with example embodiments relate to anapparatus and method for displaying a three-dimensional (3D) image.

2. Description of the Related Art

A head-up display (HUD) system may generate a virtual image in front ofa driver and display information in the virtual image, thereby providingthe user with a variety of information. The information provided to thedriver may include, for example, navigation information and dashboardinformation such as a vehicle speed, a fuel level, and an enginerevolution per minute (RPM). The driver may more easily recognize theinformation displayed in front without turning his or her gaze duringdriving, and thus, driving safety may improve. In addition to thenavigation information and the dashboard information, the HUD system mayalso provide the driver with, for example, a lane indicator, aconstruction indicator, an accident indicator, and a pedestriandetection indicator using augmented reality (AR), to assist with drivingwhen a view is not so clear.

SUMMARY

One or more example embodiments may address at least the above problemsand/or disadvantages and other disadvantages not described above. Also,the example embodiments are not required to overcome the disadvantagesdescribed above, and an example embodiment may not overcome any of theproblems described above.

According to an aspect of the disclosure, there is provided athree-dimensional (3D) display apparatus comprising: an optical layercomprising a plurality of optical elements; a projector configured toscan a light onto the optical layer; and a processor configured tocontrol a timing at which the projector scans the light onto the opticallayer and generate a 3D image in a viewing space based on the timing atwhich the light is scanned onto the optical layer.

The processor may be further configured to generate the 3D image basedon virtual scanned pixels implemented by the light scanned according tothe timing.

The processor may be further configured to generate the 3D image bycontrolling a color of the light based on the timing at which the lightis scanned onto the optical layer.

The processor may be further configured to generate the 3D image bycontrolling a plurality of light sources generating the light based on avalue of a scanned pixel corresponding to the timing at which the lightis scanned onto the optical layer.

The processor may be further configured to generate the 3D image basedon a direction of the light according to a corresponding positionalrelationship between the plurality of optical elements and the virtualscanned pixels.

The optical layer may be further configured to refract or reflect alight of a first wavelength, and transmit a light of a second wavelengthdifferent from the first wavelength.

An optical parameter of the optical layer may be determined based on aposition of the projector and a position of the viewing space.

The optical layer may be provided on or inside a windshield of avehicle.

The optical layer may comprise a holographic optical element (HOE) lensarray.

The HOE lens array may be recorded to provide the 3D image in theviewing space based on a position of the projector and a position of theviewing space.

The optical layer may comprise a lens array coated with an opticalcoating layer having a transmittance which changes based on a wavelengthof a visible light.

The projector comprises at least one laser scanning module configured toscan a laser beam onto the optical layer.

The at least one laser scanning module may comprise: a plurality oflaser light sources configured to output laser beams corresponding to aplurality of colors; a beam combiner configured to synthesize outputs ofthe plurality of laser light sources into a single integrated beam; anda scanning mirror configured to control a direction of the singleintegrated beam to scan the single integrated beam onto the opticallayer.

The 3D image may comprise an integral image forming multiple viewingzones by integrating elemental images including 3D information of atarget object.

The 3D display apparatus may further comprise: an immersion layerprovided on the optical layer, wherein the immersion layer and theoptical layer have a same refractive index.

The 3D display apparatus may further comprise: a compensating lensprovided between the projector and the optical layer, wherein thecompensating lens is configured to correct an image distortion.

According to another aspect of the disclosure, there is provided athree-dimensional (3D) display method comprising: obtaining informationrelated to a timing at which a light is scanned by a projector onto anoptical layer; controlling the timing at which the projector scans thelight onto the optical layer; and generating a 3D image in a viewingspace based on the timing at which the light is scanned onto the opticallayer.

The 3D image may be generated based on virtual scanned pixelsimplemented by the light scanned according to the timing.

The generating the 3D image may comprise controlling a color of thelight based on the timing at which the light is scanned onto the opticallayer.

The generating the 3D image may comprise controlling a plurality oflight sources generating the light based on a value of a scanned pixelcorresponding to the timing at which the light is scanned onto theoptical layer.

The 3D image may be generated based on a direction of the lightaccording to a corresponding positional relationship between a pluralityof optical elements included in the optical layer and the virtualscanned pixels.

The optical layer may be configured to refract or reflect a light of afirst wavelength, and transmit a light of a second wavelength differentfrom the first wavelength.

An optical parameter of the optical layer may be determined based on aposition of the projector and a position of the viewing space.

The optical layer may be provided on or inside a windshield of avehicle.

The optical layer may comprise a holographic optical element (HOE) lensarray.

The HOE lens array may be recorded to provide the 3D image in theviewing space based on a position of the projector and a position of theviewing space.

The optical layer may comprise a lens array coated with an opticalcoating layer having a transmittance which changes based on a wavelengthof a visible light.

The projector may comprise at least one laser scanning module configuredto scan a laser beam onto the optical layer.

The laser scanning module may comprise: a plurality of laser lightsources configured to output laser beams corresponding to a plurality ofcolors; a beam combiner configured to synthesize outputs of theplurality of laser light sources into a single integrated beam; and ascanning mirror configured to control a direction of the integrated beamto scan the integrated beam onto the optical layer.

The 3D image may comprise an integral image forming multiple viewingzones by integrating elemental images including 3D information of atarget object.

According to another aspect of the disclosure, there is provided anon-transitory computer-readable storage medium storing instructionsthat, when executed by a processor, cause the processor to perform the3D display method.

According to another aspect of the disclosure, there is provided athree-dimensional (3D) display apparatus comprising: a memory configuredto store one or more instructions; and a processor configured to executethe one or more instructions to: obtain a first timing informationassociated with a first wavelength a light; obtain a second timinginformation associated with a second wavelength of the light; control aprojector to scan the light with the first wavelength onto an opticallayer during a first timing period based on the first timing informationand scan the light with the second wavelength onto the optical layerduring a second timing period based on the second timing information;and generate the 3D image in a viewing space based on the light scannedby the projector.

The 3D display apparatus may further comprises the projector comprising:a scanning mirror configured to control a direction of the light; and alaser scanning module configured to output the light through thescanning mirror, wherein the laser scanning module is further configuredto scan the light in a vertical direction or a horizontal direction.

The 3D display apparatus may further comprise the optical layercomprising: a first optical element configured to refract or reflect alight of a first wavelength, and transmit a light of a second wavelengthdifferent from the first wavelength; and a second optical elementconfigured to refract or reflect the light of the second wavelength, andtransmit the light of the first wavelength.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects will be more apparent by describingcertain example embodiments with reference to the accompanying drawings,in which:

FIG. 1 illustrates a three-dimensional (3D) display apparatus accordingto an example embodiment;

FIG. 2 illustrates a distribution of beams output from a 3D displayapparatus according to an example embodiment;

FIG. 3 illustrates a method of implementing scanned pixels correspondingto red, green, and blue (RGB) subpixels of a panel according to anexample embodiment;

FIG. 4A illustrates a general multiview image generating method;

FIG. 4B illustrates a multiview image generating method according to anexample embodiment;

FIGS. 5A and 5B illustrate methods of implementing white (W) pixelsusing scanned pixels;

FIG. 6 illustrates a structure of a laser scanning module according toan example embodiment;

FIG. 7A illustrates a method of manufacturing a holographic opticalelement (HOE) lens array according to an example embodiment;

FIG. 7B illustrates a method of implementing an HOE lens array accordingto an example embodiment;

FIG. 8 illustrates a 3D display apparatus including a compensating lensaccording to an example embodiment;

FIG. 9 illustrates a 3D display apparatus including an immersion layeraccording to an example embodiment;

FIG. 10 illustrates a circular display apparatus using a 3D displayapparatus according to an example embodiment;

FIGS. 11A and 11B illustrate a method of implementing a 3D image usingintegral imaging according to an example embodiment; and

FIG. 12 illustrates a 3D display method according to an exampleembodiment.

FIG. 13 illustrates a structure of the 3D display apparatus according toan example embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to example embodiments, which areillustrated in the accompanying drawings, wherein like referencenumerals refer to the like elements throughout. Example embodiments aredescribed below in order to explain the disclosure by referring to thefigures.

The following structural or functional descriptions are to merelydescribe the example embodiments, and the scope of the exampleembodiments is not limited to the descriptions provided in thedisclosure. Various changes and modifications can be made to one or moreof the example embodiments by those of ordinary skill in the art.

Although terms of “first” or “second” are used to explain variouscomponents, the components are not limited to the terms. These termsshould be used only to distinguish one component from another component.For example, a “first” component may be referred to as a “second”component, or similarly, and the “second” component may be referred toas the “first” component within the scope of the right according to theconcept of the disclosure.

It will be understood that when a component is referred to as being“connected to” another component, the component can be directlyconnected or coupled to the other component or intervening componentsmay be present. In addition, it should be noted that if it is describedin the disclosure that one component is “directly connected” or“directly joined” to another component, still other component may not bepresent therebetween. Likewise, expressions, for example, “between” and“immediately between” and “adjacent to” and “immediately adjacent to”may also be construed as described in the foregoing.

As used herein, the singular forms are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It shouldbe further understood that the terms “comprises” and/or “comprising,”when used in this disclosure, specify the presence of stated features,integers, steps, operations, elements, components or a combinationthereof, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof.

Unless otherwise defined herein, all terms used herein includingtechnical or scientific terms have the same meanings as those generallyunderstood by one of ordinary skill in the art. Terms defined indictionaries generally used should be construed to have meaningsmatching with contextual meanings in the related art and are not to beconstrued as an ideal or excessively formal meaning unless otherwisedefined herein.

FIG. 1 illustrates a three-dimensional (3D) display apparatus accordingto an example embodiment.

Referring to FIG. 1, a configuration of a 3D display apparatus 100 isillustrated.

The 3D display apparatus 100 is an apparatus which implements a 3D image140, and may implement the 3D image 140, for example, by providingdifferent images to a left eye and a right eye of a user. A binoculardisparity may cause the user to experience 3D effects.

In general, a panel and a disparity separating device may be needed toimplement a 3D image. For example, the 3D display apparatus may providea 3D image by disposing the disparity separating device, for example, aparallax barrier or a lenticular lens, on a front surface of the paneland disposing appropriate view images on pixels of the panel. Thelenticular lens may control a direction of a beam propagated to a 3Dspace using a characteristic of a light being refracted when passingthrough the lens, and the parallax barrier may control a direction of abeam propagated to a 3D space by selectively transmitting a light usinga slit.

The 3D display apparatus 100 may generate the 3D image 140 using amethod of scanning a light to an optical layer 120 without using adisplay panel. FIG. 1 illustrates a head-up display (HUD) system usingthe 3D display apparatus 100, as an example. Hereinafter, for ease ofdescription, an example of the HUD system will be described. However,example embodiments of the 3D display apparatus 100 are not limited tothe HUD system, and may be applied to all kinds of display apparatusessuch as a TV, a digital information display (DID), a monitor, and amobile device in various manners.

The 3D display apparatus 100 may include a projector 110 and the opticallayer 120. The projector 110 may scan a light to the optical layer 120.The optical layer 120 may include a plurality of optical elements. Anoptical element may be a smallest unit to generate a multiview image.Lights output from the optical elements may be gathered at a pitch in aviewing space. According to an example embodiment, the pitch may be apredetermined pitch. The optical elements may also be referred to as 3Dpixels. A 3D pixel may refract or reflect only a light of a particularwavelength, and transmit a light of a wavelength other than theparticular wavelength. According to an example embodiment, theparticular wavelength may be a predetermined wavelength. According to anembodiment, the specific wavelength may be a range of wavelengths.

To refract or reflect only a light of a predetermined wavelength andtransmit a light of a wavelength other than the predeterminedwavelength, the optical layer 120 may include a lens array coated withan optical coating layer having a transmittance which changes based on awavelength of a visible light. For example, dichroic mirror coatingwhich selectively increases a reflectance with respect to apredetermined wavelength and increases a transmittance with respect tothe other wavelengths may be applied to a surface of a lens array of ageneral optical lens.

Parameters of the optical layer 120 may be determined based on aposition of the projector and a position of the predetermined viewingspace. For example, refractive indices of the optical elements includedin the optical layer 120 may be determined based on a position of theprojector and a position of the predetermined viewing space. A method ofdetermining the parameters of the optical layer 120 will be described indetail below with reference to FIG. 7A according to an exampleembodiment.

The projector 110 may scan a light of a predetermined wavelength to theoptical layer 120. A single 3D pixel to which the light is scanned bythe projector 110 may output a light in a designed direction. Accordingto an embodiment, the light may be scanned by the projector 110 for apredetermined time. Lights output from the 3D pixels may form a viewimage. The 3D display apparatus 100 may represent 3D spatial pointsusing the plurality of 3D pixels.

The 3D display apparatus 100 may render an image to be generated on theoptical layer 120. Here, “rendering” may be an operation of determiningor generating two-dimensional (2D) images to be displayed on the opticallayer 120 to provide the 3D image 140 to the user. For example,“rendering” may be an operation of generating the 2D images to bedisplayed on the optical layer 120 attached to an inner surface of awindshield 130, a front window of a vehicle, or inserted into thewindshield 130 to provide the 3D image 140 in a particular viewing spaceof the user. The particular viewing space may be a predetermined viewingspace of the user. Image information may be data related to an imagegenerated on the optical layer 120. For example, the image informationmay include data related to a size and a color of the image generated onthe optical layer 120.

According to an example embodiment, the “rendering” operation may beperformed by a processor included in the 3D display apparatus 100. Here,the processor may be implemented by hardware modules, software modules,or various combinations thereof. The processor may control the imageinformation based on a timing at which the light is scanned to theoptical layer to provide the 3D image in the predetermined viewingspace. The predetermined viewing space may refer to a space in which theuser may continuously observe the 3D image at positions of the eyes ofthe user or positions in vicinity of the eyes, even when the user movesfrom side to side.

The 3D image 140 may include a multiview image and an integral image.For example, multiview imaging may implement a 3D image by providingimages corresponding to two different viewpoints among a plurality ofviewpoints to both eyes of the user. For example, the user may view animage corresponding to a first viewpoint with the left eye and view animage corresponding to a second viewpoint with the right eye, therebyexperiencing 3D effects from a corresponding 3D image. Integral imagingmay implement a 3D image by storing 3D information of a target object ina form of elemental images using a lens array including a plurality ofelemental lenses and integrating the elemental images stored through thelens array. Integral imaging will be described further below withreference to FIGS. 11A and 11B.

FIG. 2 illustrates a distribution of beams output from a 3D displayapparatus according to an example embodiment.

Referring to FIG. 2, a projector may scan a light to an optical layer220. The projector may include at least one laser scanning module 210configured to scan a laser to the optical layer 220. The light scannedby the projector may include a laser beam scanned by the laser scanningmodule 210. A single laser scanning module may operate as a singleprojector, or at least two laser scanning modules may operate as asingle projector.

The laser scanning module 210 may be a device configured to output abeam through a scanning mirror 211 capable of direction control using areflecting mirror. The laser scanning module may output the beam afterbeams output respectively from a plurality of laser light sources arecombined through a semi-transmissive optical device. According to anexample embodiment, the plurality of laser light sources may beconfigured to output laser beams corresponding to a plurality of colors,For example, the plurality of laser light sources may be a red laserlight source, a green laser light source, and a blue laser light source.The laser scanning module 210 will be described further below withreference to FIG. 6.

The laser scanning module 210 may scan a line of a second direction, forexample, a line at a time in a lateral direction, while moving a laserbeam in a first direction toward the optical layer 220, for example,moving down from the top, by rotating the scanning mirror 211. The laserscanning module 210 may generate a 2D image on the optical layer 220through laser beam scanning. The scanning mirror of the laser scanningmodule 210 may rotate at a predetermined interval to scan a laser beamto the optical layer 220.

A plurality of beams 230 may be determined in a 3D space based on the 2Dimage represented on the optical layer 220. For example, the pluralityof beams generated in the 3D space may change based on image informationof the 2D image displayed on the optical layer 220. To output a beam ofdifferent information, for example, a different color, to a differentposition of the optical layer 220 in response to rotation of thescanning mirror, the image information and the scanning interval of thescanning mirror may be synchronized. For example, information related toa laser beam may change sequentially based on the image information andthe scanning interval.

The optical layer 220 may include a plurality of optical elements 221and 222. Scanned pixels may be implemented by changing beams to bescanned to the plurality of optical elements based on a timing at whicha laser is scanned. The scanned pixels may not be real pixels, butvirtual pixels acting as pixels implemented by laser. Laser beams may bescanned and may maintain a linear form in the optical layer 220. Thus,through on-off control of the laser beams at a predetermined timeinterval based on the image information, separate beams to be scanned tothe plurality of optical elements 221 and 222 included in the opticallayer 220 may be generated, and the scanned pixels may be implemented bythe beams. For example, a first scanned pixel corresponding to theoptical element 221 may be implemented by a laser beam 215, and a secondscanned pixel corresponding to the optical element 222 may beimplemented by the laser beam 215 while moving the laser beam 215 downfrom the top by rotating the scanning mirror 211.

Propagation directions of beams output from optical elements may bedetermined based on directions of beams according to a correspondingpositional relationship between the optical elements and scanned pixels,and thus 3D spatial points may be represented.

FIG. 3 illustrates a method of implementing scanned pixels correspondingto red, green, and blue (RGB) subpixels of a panel according to anexample embodiment.

Referring to FIG. 3, a 3D display apparatus may control imageinformation by controlling a color of a light based on a timing at whichthe light is scanned to an optical layer.

As described above, to separate a spatial 3D image, the 3D displayapparatus may dispose a disparity separating device, for example, aparallax barrier or a lenticular lens, on a front surface of a panel andmay dispose appropriate view image on pixels of the panel, therebyproviding a 3D image.

A general RGB panel 310 may have a pixel structure in which a red (R)subpixel, a green (G) subpixel, and a blue (B) subpixel are included ina single pixel. The 3D display apparatus may provide a 3D image usingscanned pixels, instead of pixels of a real panel. In detail, thescanned pixels may be implemented by controlling RGB laser light sourcesbased on image information at scanning timings corresponding topositions of the RGB subpixels.

For example, a red (R) scanned pixel may be formed by outputting only ared (R) laser beam 320 and not outputting, but rather blocking a green(G) laser beam 330 and a blue (B) laser beam 340 at a scanning timingcorresponding to the position of the R subpixel of the RGB panel 310. Agreen (G) scanned pixel and a blue (B) scanned pixel may be formed onthe same principle based on the positions of the G subpixel and the Bsubpixel.

Further, by adjusting a brightness of a beam through modulation of anoutput laser beam of each laser light source based on the imageinformation simultaneously with on-off control of the RGB laser lightsources at a predetermined time interval based on the image information,a color of a scanned pixel may be controlled.

FIG. 4A illustrates a general multiview image generating method, andFIG. 4B illustrates a multiview image generating method according to anexample embodiment. Before the multiview image generating method isdescribed with reference to FIG. 4B, general multiview displaying usinga panel will be described in brief with reference to FIG. 4A.

FIG. 4A shows directions in which beams output from a plurality ofpixels included in a panel 400 are propagated to a 3D space, when ageneral multiview display is used to implement autostereoscopic 3Ddisplay. The beams generated from the pixels of the panel 400 maypropagate uniformly toward a user, having a predetermined direction by alenticular lens attached to a front surface of the panel 400. When leftand right images of different viewpoints are applied to pixelsgenerating beams to be incident to left and right eyes of the user, theuser may perceive a 3D image. Each pixel may include subpixels. Forexample, a single pixel may include RGB subpixels.

FIG. 4B shows directions in which beams output from scanned pixelscorresponding to RGB subpixel of a panel are propagated in a 3D spaceusing a projector, rather than using a panel 400, when a 3D displayapparatus according to an example embodiment is used.

The 3D display apparatus may include the projector and an optical layer.The optical layer may correspond to a lenticular lens of a generalmultiview-based 3D display apparatus, in that the optical layer mayoutput a light scanned from the projector as beams including differentinformation in many directions. Although the 3D display apparatus doesnot include a panel 400, the 3D display apparatus may generate scannedpixels corresponding to RGB subpixels by scanning the light to theoptical layer through the projector.

For example, the scanned pixels may be generated through on-off controlof RGB laser light sources at a predetermined time interval based onimage information at scanning timings corresponding to positions of RGBsubpixels. When the light scanned from the projector is adjusted tocorrespond to the positions of the subpixels of the panel of FIG. 4A, a3D image may be implemented in a manner similar to that of the generalmultiview-based 3D display apparatus.

FIGS. 5A and 5B illustrate methods of implementing white (W) pixelsusing scanned pixels. In a first example 510 illustrated in FIG. 5A, a3D display apparatus may implement W scanned pixels by controllingon-off of RGB laser light sources based on timings of scanned pixelunits, and represent a gray level of a beam through modulation at thesame time. In a second example 520 illustrated in FIG. 5B, the 3Ddisplay apparatus may implement W scanned pixels by controlling on-offof RGB laser light sources based on timings of subpixel units in ascanned pixel.

In another example, as shown in FIG. 3, W scanned pixels may beimplemented by controlling a brightness of each subpixel to beidentical, without simultaneously controlling on-off of subpixels in ascanned pixel.

FIG. 6 illustrates a structure of a laser scanning module according toan example embodiment.

Referring to FIG. 6, a laser scanning module 600 may include a red (R)laser light source 612 configured to output a red laser beam, a green(G) laser light source 611 configured to output a green laser beam, ablue (B) laser light source 613 configured to output a blue laser beam,condensers C1, C2, and C3 configured to concentrate lights output fromthe R, G, and B laser light sources, beam combiners 621 and 622configured to synthesize outputs of the plurality of laser light sourcesinto a single integrated beam, at least one reflecting mirror 630configured to control a path of the beam, and a scanning mirror 640configured to control a direction of the integrated beam to scan theintegrated beam to an optical layer.

The beam combiners 621 and 622 may include dichroic mirrors 621 a and622 a configured to reflect only lights of predetermined wavelengthsgenerated from the R, G, and B laser light diodes and concentratedthrough the condensers and transmit lights of the other wavelengths. Forexample, the dichroic mirror 621 a may have a characteristic ofreflecting only a red laser beam, and the dichroic mirror 622 a may havea characteristic of reflecting only a blue laser beam. A green beam maypass through the dichroic mirrors 621 a and 622 a, and a red beam maypass through the dichroic mirror 622 a. Thus, the outputs of the RGBlaser light sources may be synthesized into a single integrated beamusing the dichroic mirrors 621 a and 622 a.

The scanning mirror 640 may be manufactured using micro electromechanical system (MEMS) technology, and generate a 2D image by scanninglaser beams focused on a single point to the optical layer using twodriving axes. The 2D image may be implemented as a set of horizontallines of which positions are different in a vertical direction.

The laser scanning module 600 may be simply structured and easilyminiaturized and thus, utilized as a handheld projector. Further, byincreasing a scanning angle of the scanning mirror 640, a field of viewmay be easily increased. For example, it may be difficult in practice tomount a HUD system of a great size due to a limited space in a dashboardof a vehicle. When the HUD system is configured using the laser scanningmodule 600, a 3D HUD image with a wide field of view may be provided toa driver.

FIG. 7A illustrates a method of manufacturing a holographic opticalelement (HOE) lens array according to an example embodiment.

Referring to FIG. 7A, an optical layer may include an HOE lens array. AnHOE may have a narrow wavelength bandwidth and be used as an opticaldevice only in a region of a predetermined wavelength. The HOE lensarray may be manufactured using a general optical lens array 710 and aphotopolymer 720. The HOE lens array may be recorded, for example, onthe photopolymer, in view of a position of a projector and a position ofa predetermined viewing space. Recording the HOE lens array may bedetermining optical parameters of a plurality of optical elementsincluded in the HOE lens array acting as an optical layer. For example,refractive indices of the optical elements included in the optical layer120 or 220 may be determined in view of the position of the projectorand the position of the predetermined viewing space.

The HOE lens array may be recorded using a reference beam incident fromthe position of the projector toward the general optical lens array 710and the photopolymer 720 at a predetermined divergence angle α and asignal beam horizontally proceeding toward the predetermined viewingspace in a state in which the general optical lens array 710 and thephotopolymer 720 overlap. Although FIG. 7A illustrates the generaloptical lens array 710 being provided in a vertical direction, thegeneral optical lens array 710 may also be manufactured in a horizontaldirection or in both, vertical and horizontal, directions.

FIG. 7B illustrates a method of implementing an HOE lens array accordingto an example embodiment.

Referring to FIG. 7B, an HOE lens array 730 may be manufactured torefract or reflect only a light of a predetermined wavelength and totransmit a light of a wavelength other than the predeterminedwavelength, and thereby act as a disparity separating device, forexample, a parallax barrier or a lenticular lens. For example, the HOElens array 730 manufactured using the method described with reference toFIG. 7A may respond only to RGB laser beams and transmit lights of theother wavelengths.

When a projector 740 is disposed at a position the same as that forrecording and a light is scanned to the HOE lens array 730 at apredetermined divergence angle α, a user may observe a 3D image at aposition of a predetermined viewing space 750.

FIG. 8 illustrates a 3D display apparatus including a compensating lensaccording to an example embodiment.

Referring to FIG. 8, a HUD system using the 3D display apparatus 100 isillustrated. The 3D display apparatus 100 may further include acompensating lens 850.

The compensating lens 850 may be an image distortion correcting device.According to an example embodiment, by additionally providing thecompensating lens 850 between the projector 110 and an optical layer 820to correct an image distortion, a burden of the optical layer 120 may bereduced.

In another example embodiment, when manufacturing an HOE lens array, aplurality of HOE layers may be provided such that one layer may act as alens array, and the other layer may perform a function to correct animage distortion.

FIG. 9 illustrates a 3D display apparatus including an immersion layeraccording to an example embodiment.

An optical layer 910 may refract or reflect only a light of apredetermined wavelength and transmit a light of a wavelength other thanthe predetermined wavelength. For example, the optical layer 910 mayrespond only to a laser beam scanned by a projector without affecting atransmittance of an external light using a wavelength selectivity,thereby removing a visibility by the external light.

Referring to FIG. 9, to remove the visibility by the external light, animmersion layer 920 may be applied to the optical layer 910. Accordingto an example embodiment, the immersion layer 920 may have an opticalcoating which selectively increases a reflectance with respect to awavelength of a light scanned by the projector and increases atransmittance with respect to the other wavelengths. The immersion layer920 and the optical layer 910 may have the same refractive index. Forexample, a refractive index n1 of the optical layer 910 may be identicalto a refractive index n2 of the immersion layer 920. Using the immersionlayer 920 having a refractive index identical to that of the opticallayer 910, a distortion occurring at a target observed through theoptical layer 910 may be prevented.

FIG. 10 illustrates a circular display apparatus using a 3D displayapparatus according to an example embodiment. The description providedwith reference to FIGS. 1 through 9 may also apply to FIG. 10, and thusduplicate description will be omitted for conciseness.

Referring to FIG. 10, a cylindrical display apparatus 1000 using a 3Ddisplay apparatus may include a projector 1010 and an optical layer1020. The optical layer 1020 may have a shape of a side of a cylinder.Hereinafter, for ease of description, a cylindrical display apparatuswill be described. However, examples of the 3D display apparatus are notlimited to the cylindrical display apparatus, and applied in variousshapes.

The projector 1010 may scan a light to the optical layer 1020 through a360-degree rotation. The cylindrical display apparatus 1000 mayrepresent 3D spatial points using a plurality of optical elements 1021and 1022 for a user to view at eyebox 1030.

FIGS. 11A and 11B illustrate a method of implementing a 3D image usingintegral imaging according to an example embodiment.

Referring to FIGS. 11A and 11B, a general integral imaging-basedstereoscopic image display apparatus may include an image pickup 1100 asillustrated in FIG. 11A and a display 1150 as illustrated in FIG. 11B.According to an example embodiment, the image pickup 1100 may convert 3Dinformation of a 3D object 1120 into a whole elemental image using acapturing device 1140, such as a camera and a first lens array 1130, andthe image pickup 1100 may store the elemental image in the capturingdevice 1140.

According to an example embodiment, the display 1150 may include adisplay panel 1160 and a second lens array 1170, and present the wholeelemental image displayed on the display panel 1160 in a form of astereoscopic image 1180 in a predetermined viewing space 1190.

According to general integral imaging, multiple viewing zones withdifferent viewpoints may be formed. The integral imaging-based 3D imagedisplay apparatus may use a micro lens array as an optical array. Whenthe micro lens array is used, beams output from the optical array may becontrolled to be separated into left and right images in the viewingspace.

For the 3D display apparatus to generate a 3D image according tointegral imaging, an HOE lens array may be recorded in view of aposition of a projector and a position of the predetermined viewingspace such that the HOE lens array may act as the micro lens array.

According to an example embodiment, the description and features of oneor more example embodiments in FIGS. 1 through 10 may also apply toFIGS. 11A and 11B, and thus duplicate description will be omitted forconciseness. For example, when implementing a 3D image according tointegral imaging, scanned pixels as illustrated in FIG. 2 may outputimages corresponding to direction angles assigned to the correspondingpixels. A direction angle is an angle at which a beam is projected froma scanned pixel. By projecting the output images to the correspondingscanned pixels at predetermined direction angles, a 3D image may beimplemented.

FIG. 12 illustrates a 3D display method according to an exampleembodiment.

Operations 1210 and 1220 may be performed by the 3D display apparatus100 of FIG. 1. The 3D display apparatus 100 may be implemented using oneor more hardware modules, one or more software modules, or variouscombinations thereof.

In operation 1210, the 3D display apparatus 100 may obtain informationrelated to a timing at which a light is scanned to an optical layer toprovide a 3D image in a predetermined viewing space. For example, inoperation 1210, the 3D display apparatus may obtain information about afirst timing at which a red (R) scanned pixel may be formed, a secondtiming at which a green (G) scanned pixel may be formed, and a thirdtiming at which the blue (B) scanned pixel may be formed.

In operation 1220, the 3D display apparatus 100 may control imageinformation generated on the optical layer based on the informationrelated to the timing at which the light is scanned. According to anexample embodiment, during the first timing the 3D display apparatus mayoutput only a red (R) laser beam to the position of the R subpixel ofthe RGB panel 310, but refrain from outputting the green (G) and blue(B) laser beams. For instance, the 3D display apparatus may block thegreen (G) laser beam 330 and the blue (B) laser beam 340 at the firsttiming. A green (G) scanned pixel may be formed at a second timing and ablue (B) scanned pixel may be formed at a third timing based on the sameprinciple described about with regard to the red (R) scanned pixel andbased on the positions of the G subpixel and the B subpixel.

FIG. 13, the illustrates a structure of the 3D display apparatus 1300according to an example embodiment. The 3D display apparatus 1300 mayinclude a processor 1330, a memory 1350 and a communication interface1370, which are all connected to and communicate with each other via aus 1305. According to an example embodiment, the “rendering” operationmay be performed by the processor 1330. The processor 1330 may controlthe image information based on a timing at which the light is scanned tothe optical layer to provide the 3D image in the predetermined viewingspace. The predetermined viewing space may refer to a space in which theuser may continuously observe the 3D image at positions of the eyes ofthe user or positions in vicinity of the eyes, even when the user movesfrom side to side.

According to an embodiment, the processor 1330 may communicate with thememory 1350 to store data, retrieve data or retrieve instruction relatedto performing the control of the image information. According to exampleembodiment, the communication interface 1370 may be configured toreceive external input information and provide the received informationto the memory 1350 or the processor 1330. According to exampleembodiment, the communication interface 1370 may be configured to outputinformation processed by the processor 1330 or retrieved from thememory.

According to an embodiment, the memory 1350 may be configured to storeone or more instructions; and the processor 1330 may be configured toexecute the one or more instructions to: obtain a first timinginformation associated with a first wavelength of a light, obtain asecond timing information associated with a second wavelength of thelight, control a projector to scan the light with the first wavelengthonto an optical layer during a first timing period based on the firsttiming information and scan the light with the second wavelength ontothe optical layer during a second timing period based on the secondtiming information and generate the 3D image in a viewing space based onthe light scanned by the projector.

The example embodiments described herein may be implemented using ahardware component, a software component and/or a combination thereof. Aprocessing device may be implemented using one or more general-purposeor special purpose computers, such as, for example, a processor, acontroller and an arithmetic logic unit (ALU), a DSP, a microcomputer,an FPGA, a programmable logic unit (PLU), a microprocessor or any otherdevice capable of responding to and executing instructions in a definedmanner. The processing device may run an operating system (OS) and oneor more software applications that run on the OS. The processing devicealso may access, store, manipulate, process, and create data in responseto execution of the software. For purpose of simplicity, the descriptionof a processing device is used as singular; however, one skilled in theart will appreciated that a processing device may include multipleprocessing elements and multiple types of processing elements. Forexample, a processing device may include multiple processors or aprocessor and a controller. In addition, different processingconfigurations are possible, such a parallel processors.

The software may include a computer program, a piece of code, aninstruction, or some combination thereof, to independently orcollectively instruct or configure the processing device to operate asdesired. Software and data may be embodied permanently or temporarily inany type of machine, component, physical or virtual equipment, computerstorage medium or device, or in a propagated signal wave capable ofproviding instructions or data to or being interpreted by the processingdevice. The software also may be distributed over network coupledcomputer systems so that the software is stored and executed in adistributed fashion. The software and data may be stored by one or morenon-transitory computer readable recording mediums.

The methods according to the above-described example embodiments may berecorded in non-transitory computer-readable media including programinstructions to implement various operations of the above-describedexample embodiments. The media may also include, alone or in combinationwith the program instructions, data files, data structures, and thelike. The program instructions recorded on the media may be thosespecially designed and constructed for the purposes of exampleembodiments, or they may be of the kind well-known and available tothose having skill in the computer software arts. Examples ofnon-transitory computer-readable media include magnetic media such ashard disks, floppy disks, and magnetic tape; optical media such asCD-ROM discs, DVDs, and/or Blue-ray discs; magneto-optical media such asoptical discs; and hardware devices that are specially configured tostore and perform program instructions, such as read-only memory (ROM),random access memory (RAM), flash memory (e.g., USB flash drives, memorycards, memory sticks, etc.), and the like. Examples of programinstructions include both machine code, such as produced by a compiler,and files containing higher level code that may be executed by thecomputer using an interpreter. The above-described devices may beconfigured to act as one or more software modules in order to performthe operations of the above-described example embodiments, or viceversa.

A number of example embodiments have been described above. Nevertheless,it should be understood that various modifications may be made to theseexample embodiments. For example, suitable results may be achieved ifthe described techniques are performed in a different order and/or ifcomponents in a described system, architecture, device, or circuit arecombined in a different manner and/or replaced or supplemented by othercomponents or their equivalents. Accordingly, other implementations arewithin the scope of the following claims.

What is claimed is:
 1. A three-dimensional (3D) display apparatuscomprising: an optical layer comprising a plurality of optical elements;a projector configured to scan a light onto the optical layer; and aprocessor configured to control a timing at which the projector scansthe light onto the optical layer and generate a 3D image in a viewingspace based on the timing at which the light is scanned onto the opticallayer.
 2. The 3D display apparatus of claim 1, wherein the processor isfurther configured to generate the 3D image based on virtual scannedpixels implemented by the light scanned according to the timing.
 3. The3D display apparatus of claim 1, wherein the processor is furtherconfigured to generate the 3D image by controlling a color of the lightbased on the timing at which the light is scanned onto the opticallayer.
 4. The 3D display apparatus of claim 1, wherein the processor isfurther configured to generate the 3D image by controlling a pluralityof light sources generating the light based on a value of a scannedpixel corresponding to the timing at which the light is scanned onto theoptical layer.
 5. The 3D display apparatus of claim 2, wherein theprocessor is further configured to generate the 3D image based on adirection of the light according to a corresponding positionalrelationship between the plurality of optical elements and the virtualscanned pixels.
 6. The 3D display apparatus of claim 1, wherein theoptical layer is further configured to refract or reflect a light of afirst wavelength, and transmit a light of a second wavelength differentfrom the first wavelength.
 7. The 3D display apparatus of claim 1,wherein an optical parameter of the optical layer is determined based ona position of the projector and a position of the viewing space.
 8. The3D display apparatus of claim 1, wherein the optical layer is providedon or inside a windshield of a vehicle.
 9. The 3D display apparatus ofclaim 1, wherein the optical layer comprises a holographic opticalelement (HOE) lens array.
 10. The 3D display apparatus of claim 9,wherein the HOE lens array is recorded to provide the 3D image in theviewing space based on a position of the projector and a position of theviewing space.
 11. The 3D display apparatus of claim 1, wherein theoptical layer comprises a lens array coated with an optical coatinglayer having a transmittance which changes based on a wavelength of avisible light.
 12. The 3D display apparatus of claim 1, wherein theprojector comprises at least one laser scanning module configured toscan a laser beam onto the optical layer.
 13. The 3D display apparatusof claim 12, wherein the at least one laser scanning module comprises: aplurality of laser light sources configured to output laser beamscorresponding to a plurality of colors; a beam combiner configured tosynthesize outputs of the plurality of laser light sources into a singleintegrated beam; and a scanning mirror configured to control a directionof the single integrated beam to scan the single integrated beam ontothe optical layer.
 14. The 3D display apparatus of claim 1, wherein the3D image comprises an integral image forming multiple viewing zones byintegrating elemental images including 3D information of a targetobject.
 15. The 3D display apparatus of claim 1, further comprising: animmersion layer provided on the optical layer, wherein the immersionlayer and the optical layer have a same refractive index.
 16. The 3Ddisplay apparatus of claim 1, further comprising: a compensating lensprovided between the projector and the optical layer, wherein thecompensating lens is configured to correct an image distortion.
 17. Athree-dimensional (3D) display method comprising: obtaining informationrelated to a timing at which a light is scanned by a projector onto anoptical layer; controlling the timing at which the projector scans thelight onto the optical layer; and generating a 3D image in a viewingspace based on the timing at which the light is scanned onto the opticallayer.
 18. The 3D display method of claim 17, wherein the 3D image isgenerated based on virtual scanned pixels implemented by the lightscanned according to the timing.
 19. The 3D display method of claim 17,wherein the generating the 3D image comprises controlling a color of thelight based on the timing at which the light is scanned onto the opticallayer.
 20. The 3D display method of claim 17, wherein the generating the3D image comprises controlling a plurality of light sources generatingthe light based on a value of a scanned pixel corresponding to thetiming at which the light is scanned onto the optical layer.
 21. The 3Ddisplay method of claim 18, wherein the 3D image is generated based on adirection of the light according to a corresponding positionalrelationship between a plurality of optical elements included in theoptical layer and the virtual scanned pixels.
 22. The 3D display methodof claim 17, wherein the optical layer is configured to refract orreflect a light of a first wavelength, and transmit a light of a secondwavelength different from the first wavelength.
 23. The 3D displaymethod of claim 17, wherein an optical parameter of the optical layer isdetermined based on a position of the projector and a position of theviewing space.
 24. The 3D display method of claim 17, wherein theoptical layer is provided on or inside a windshield of a vehicle. 25.The 3D display method of claim 17, wherein the optical layer comprises aholographic optical element (HOE) lens array.
 26. The 3D display methodof claim 25, wherein the HOE lens array is recorded to provide the 3Dimage in the viewing space based on a position of the projector and aposition of the viewing space.
 27. The 3D display method of claim 17,wherein the optical layer comprises a lens array coated with an opticalcoating layer having a transmittance which changes based on a wavelengthof a visible light.
 28. The 3D display method of claim 17, wherein theprojector comprises at least one laser scanning module configured toscan a laser beam onto the optical layer.
 29. The 3D display method ofclaim 28, wherein the laser scanning module comprises: a plurality oflaser light sources configured to output laser beams corresponding to aplurality of colors; a beam combiner configured to synthesize outputs ofthe plurality of laser light sources into a single integrated beam; anda scanning mirror configured to control a direction of the integratedbeam to scan the integrated beam onto the optical layer.
 30. The 3Ddisplay method of claim 17, wherein the 3D image comprises an integralimage forming multiple viewing zones by integrating elemental imagesincluding 3D information of a target object.
 31. A non-transitorycomputer-readable storage medium storing instructions that, whenexecuted by a processor, cause the processor to perform the 3D displaymethod of claim
 17. 32. A three-dimensional (3D) display apparatuscomprising: a memory configured to store one or more instructions; and aprocessor configured to execute the one or more instructions to: obtaina first timing information associated with a first wavelength a light;obtain a second timing information associated with a second wavelengthof the light; control a projector to scan the light with the firstwavelength onto an optical layer during a first timing period based onthe first timing information and scan the light with the secondwavelength onto the optical layer during a second timing period based onthe second timing information; and generate the 3D image in a viewingspace based on the light scanned by the projector.
 33. The 3D displayapparatus according to claim 32, further comprising: the projectorcomprising: a scanning mirror configured to control a direction of thelight; and a laser scanning module configured to output the lightthrough the scanning mirror, wherein the laser scanning module isfurther configured to scan the light in a vertical direction or ahorizontal direction.
 34. The 3D display apparatus according to claim32, further comprising: the optical layer comprising: a first opticalelement configured to refract or reflect a light of a first wavelength,and transmit a light of a second wavelength different from the firstwavelength; and a second optical element configured to refract orreflect the light of the second wavelength, and transmit the light ofthe first wavelength.